1. Field of the Invention
The present invention relates to an optical detecting apparatus, and particularly relates to an optical detecting apparatus utilizing a flank light source.
2. Description of the Prior Art
A conventional optical detecting apparatus, such as an optical touch panel, utilizes a light source to illuminate an object such as a finger on a detecting surface in a bottom to up direction, to acquire location information of the object.
FIG. 1 are schematic diagrams illustrating a conventional optical detecting apparatus 100. FIG. 1(a) is a cross-sectional view of the conventional optical detecting apparatus 100, and FIG. 1(b) is a circuit block diagram illustrating a circuit inside the optical detecting apparatus 100, which can control the operation of the optical detecting apparatus 100. The optical detecting apparatus 100 includes a detecting surface 103, alight source 105, an image sensor 107, lens 109, 111, a processor 113, a storage apparatus 115 and a light source controlling unit 117. The light source 105 is controlled by the light source control unit 117 to illuminate the finger 101 on the detecting surface 103 to generate an image. The image sensor 107 captures frames in the image. The processor 113 computes location information of the finger 101 according to captured frames. Additionally, the processor 113 controls data accessing of the storage apparatus 115 and operation of the light source controlling unit 117 as well.
However, in the above-mentioned structure, the light is emitted in a bottom to up direction, thus a larger apparatus thickness is needed. Also, under such structure, the light from the light source may needs reflection or refraction for more than one time, thus a complicated light path is needed. Also, the image signal generated from the finger may decade after reflection or refraction for more than one time, thus an unclear image may be generated.